Internal combustion engine of the diesel type



Nov. 4, 1958 H. HOFFMANN 2,358,810

' INTERNAL COMBUSTION ENGINE OF THE DIESEL TYPE Filed March 22, 1955 HE'I' NR1 C HOFFMAN 8) 01464: on!

I United States Patent restricting the same.

' INTERNAL COMBUSTION ENGINE OF THE DIESEL TYPE Heinrich Hotfmann, Stuttgart-Unterturkheim, Germany,

assignor to Daimler-Benz Aktiengesellschaft, Stuttgart- Unterturkheim, Germany Application March 22, 1955, Serial No. 496,000

Claims priority, application Germany March 27, 1954 Claims; (Cl. 123-32) My invention relates to an internal combustion engine of the diesel type in which the fuel is injected into a vortex of compressed air, and it is the object of the present invention to so correlate and organize the various elernents of the engine as to secure a high efficiency and a sinooth operation of the engine.

Further objects of my invention will appear from a detailed description of a number of embodiments thereof following hereinafter and the features of novelty will be pointed out in the claims. I wish it to be clearly understood, however, that such detailed description serves the purpose ofillustrating the invention rather than that of In the drawings,

Fig. 1 represents an axial section through the upper part of a cylinder, the cylinder head and the piston, the fuel injection nozzle being shown in elevation,

Fig. 2 is a sectional view similar to a part of Fig. 1 showing a modified structure.

Fig. 3 is a'partial section through an internal combus-' tion engine similar to Fig. 1 illustrating a modification thereof, and

Fig. 4 is a similar sectional view of still another modification,

My improved internal combustion engine of the diesel type comprises a cylinder 10, a piston 11 reciprocably mounted therein, a cylinder head 12, and a fuel injection nozzle 17. The piston 11 is shown in its upper dead center position, its plane end face confining a narrow flat compression space 13 with the flat bottom of the cylinder head 12. Both the cylinder and the cylinder head are provided with a water-cooling jacket in the conventional manner. Moreover, the cylinder head is provided with a rotund, preferably spherical, chamber disposed substantially tangentially'to the plane bottom surface of the head 12 and With a passageway 16 establishing a communication between the compression space 13 of the cylinder and the chamber 15. The passageway 16 extends substantially tangentially to the chamber 15 so as to cause the air entering the chamber 15 through the passageway 16 during the compression stroke of the piston 11 to form a vortex indicated by the arrow x. Preferably, the vortex chamber 15 is disposed laterally of a pair of valves not shown with which the cylinder head 12 is equipped for the admission of combustion air into the cylinder and for the exhaust of the combustion gases therefrom. A dash-dotted line 14 indicates a plane in which the axes of the pair of valves are located, such plane extending at right angles to the drawing. Hence, it will appear that the vortex chamber is located lateral- 1y above the cylinder space, and that the passageway 16 connecting the vortex chamber 15 with the compression space 13 is inclined, its axis being indicated by the dashdotted line 21.

It will be noted from Fig. 1 that the axis 21 is spaced from the center of the chamber 15 and extends at an acute angle to the axis of the cylinder 10.

A fuel injection nozzle 17 is so mounted as to issue 2,858,810 Patented Nov. 4, 1958 jet 18 of fuel upon the wall of the vortex chamber 15 at an acute angle thereto, said jet being directed substantially in the direction of the air flow in the vortex, that is to say in the direction of the arrow x. For such purpose, the fuel injection nozzle 17 is mounted in an inclined bore of the cylinder 10 and projects through a bore of the cylinder head 12 into the vortex chamber 15 closely adjacent to the passageway 16. The bore thus provided both in the cylinder and the cylinder head intersects at an acute angle the plane bottom surface of the cylinder head fitted upon the cylinder and terminates in close proximity to the passageway 16.

In a preferred embodiment of my invention the jet 18 comprises all of the fuel injected, as-illustrated in Fig. 4. Alternatively, however, the fuel injection nozzle may be provided with one or more additional ports to spray part of the fuel towards the center of chamber 15 transversely to the passageway 16, as indicated at 20 in Fig. 1.

The fuel injected in the direction of the arrow x in form of the jet 18 upon the region 19 of the wall of the chamber 15 will be spread on the wall of the chamber so as to form a thin layer thereon which subsequently will be partly or entirely vaporized. The vapor will be carried along by and distributed in the air by the vortex. It will be noted that in all of the embodiments of my invention described hereinabove the distance e of the tip of the nozzle from the cylinder of the engine is shorter than the distance d of the tip of the nozzle from the center C of the chamber 15. Moreover it will be noted that the radius r of the chamber 15 is larger than the distance d and that the spherical chamber 15 is disposed substantially tangentially to the bottom surface of the cylinder head. When the fuel injection commences, an extremely high temperature is abruptly produced near the tip of the nozzle and the consequent sudden expansion of the gases could interfere with the desired expulsion of the gases from the chamber into the cylinderunless .the location issued were chosen in an appropriate manner.

bustion of the injected fuel is somewhat retarded and distributed over a longer period of time, whereby a smoother operation of the diesel engine will be attained. It is highly desirable, therefore, that the distance between 'the nozzle; and the region 19 be comparatively short. For this reason,the point from which the fuel is injected is located within the chamber 15 eccentrically-at a close distance from the wall of the chamber 15. i v The jet 20 which extends transversely to the flow of air through the passageway 16 towards the center of the I immediate combustion.

chamber and the opposed Wall portions of the latter will carry' the fuel globules into the core of the vortex for If desired, the nozzle ports forming the jets 18 and 20 may be replaced, as shown in Fig. 3, by a single port so shaped as to produce a wide angle spray causing part of the fuel to be spread on the vortex chamber-and is subsequently distributed in vaporized'condition by the air vortexover the air--contents 3 effectively Water-cooled.

While it has been proposed prior to my' invention to spray the fuel at an acute-angle upon the wall of a vortex the radius of said spherical chamber.

2. Internal combustion engine of the Diesel type comprising-a cylinder, a piston reciprocably mounted'therein, a cylinder head mounted on said cylinder and provided with a spherical chamber disposed substantially tangentially to the bottom surface of said cylinder head and with a passageway establishinga communication between the iuternaltspaceof said cylinder and said chamber, the axis of said passageway being spaced from the center of said chamber and projecting at an acute angle to the axis of 61131111361",- su chvortexchamber was located-Withi'n-the l nsaidrcylindertso as .toxcause the air entering said chamber f piston. My invention" differs from such prior artby the through saidpassageway during the compression stroke absenceof any vortex chamber-in the--pistor i.";-Thereof said piston to form -a vortex, said cylinder head being fore, 'I may use a'simple piston having a flat'plane end further provided with a cooling, jacket for said'spherical Wall which results in' more favorable thermal stresses chamber, and a fuel injection nozzle mounted to issue I of the'piston end'wall; The provision of the vortex ajet of' fuel from a point located within said chamber chamber in the cylinderhead offers the advantage that between the center and the wall thereof adjacent to said the walls thereof may be effectively-cooled by water or cylinder and to said passageway in a direction away from byanother suitable medium. the latter upon a region of the internal wall of said cham- In the embodiment shown the region19 of the'wall ber atan acuteangle thereto, said region being so disof the vortex chamber on which all'of the fuel or-a major 20 posed with respect to said cooling jacket as to be effecportionthereof is sprayed is integral with the remaining 'tively water-cooled, the distance of said point from the a. portions of the wall. Ifdesired, however, the region 19 center of said chamber being shorter than the radius 0 may'be formed 'by 'a special insert.- That'is shown in 'said'spherical chamber.

Fig. 2 in which such insert 119 constitutes the region 3. Internal combustion engine of the Diesel type com- ".f impingedbythe'jet 18. The insert 119 is inserted in an 'prising a cylinder, a piston reciprocably. mounted therein, internal recess of the wall of chamber 15 and is insua cylinder head provided with a spherical chamber disf'lated from the-bottom of such recess by a disk 22 of a posed substantially tangentionally to the bottom surface suitable heat 'insulating material. of said cylinder head and with a passageway establishing While all of the fuel to be injected may be sprayed a communication between the internal space of said cylupon the-region 19 or the insert 119 for subsequent inder and said chamber, the axis of said passageway being 'vaporization, a' substantial part of the liquid maybe inspaced from the center of said chamber and extending at jectedtrans'versely or'at an angle to the stream of air an :acute angle to the axis of said cylinder so as to cause "entering the'chamber 15 through the passageway 16, the airentering said chamber through said passageway whereby such part of the fuel will be immediately ignited during the compression stroke of said piston to form a and "burned. In this manner, a more even distribution vortex, and a fuel injection nozzle mounted to spray all of the fuelin the air maybe attained. of the fuel on the wall of said chamber at an acute angle Whiletheinvention has been. described'inconn'ection "thereto in the direction of the air-flow in said vortex withseveraPdifierent embodiments thereof, it will be froma point located within said chamber excentrically understood that it is capable of further modification; and 40 at a close distance from said wall and from said cylinder, this'application'isintended to cover any variations, uses, the distance of said point from the center of said chamo r adaptations of the invention following, in general, her being shorter than the radius of said spherical chamthe principles of' 'the invention and including such depar- I bar, tures from the present disclosure as come within known 4. .Internal combustion engine as claimed inclaimZ in or'custor'narypractice in the art to which the invention which said cylinder head has a plane bottom surface pertains, and as'fall'within the scope of the invention or :fitted upon said cylinder, the latter and said cylinderhead the limits 'of'the appended claims. being provided with a bore intersecting said surface at What I claim is: an acute angle and terminating in said spherical chamber 1. Internal combustion engine of the 'Diesel type com- I in close proximity to said passageway, said bores accomprising a cylinderQa piston reciprocably'mountedtherein, modating aid fuel injection nozzle. a cylinder head provided withv a spherical chamber dis- 5. Internal, combustion engine as claimed in claim 2 Posed Substantially n i lly to the bottom surface of in which said fuel injection nozzle is constructed to issue S cylinder head and with a'passagewfly establishing a jet of fuel substantially from said point toward the a' communication between the internal space of said cy1-, center of said chamber transversely to said passageway. inder and said chamber; the axis of said passageway being spaced from the center of said chamber and extending References Ci d i h fil of hi patent at an'acute angle to the axis of said cylinder .so as to cause the air entering 'said chamber through said pas- UNITED STATES PATENTS sageway' during the compression stroke of said piston to 2,061,826 Bremser Nov. 24, 1936 form a vortex, and a fuel injection nozzle mounted with- 2,169,381 Chapman Aug. 15, 1939 in said cylinder" and said cylinder head and projecting into 2,204,068 Chapman June 11, 1940 said chamber to issue a jetof fuel from a poi'nt'jlocated withinsaid chamber between the center and the wall there- FOREIGN PATENTS ofadjacent to said cylinder and to said'passageway in a 340,069 Great Britain Dec. 24, 1930 direction away from the latter upon the wall' of said 400,173 Great Britain Oct. 12, 1933 chamber at an acute angle thereto, .the distance' of said 486,208 Great Britain June 1, 1938 point from the center of said chamber beingshorter than a 638,257 Germany Nov. 12, 1936 

